Re: [lojban] Lojban CFG Questions

[Robin Lee Powell <rlpowell@digitalkingdom.org>]

On Fri, Dec 10, 2010 at 07:20:29PM -0300, Jorge Llambías wrote:
> On Fri, Dec 10, 2010 at 6:24 AM, Roman Naumann
> <roman_naumann@fastmail.fm> wrote:
> >
> > We have five kinds (sub)sentences. They start and terminate with
> > 'a', 'b', 'c', 'd', 'e'. Inside a (sub)sentence, only
> > subsentences with a letter later in alphabet may stand. ("a c c
> > a" is thus valid, "b a a b" is invalid [whitespace ignored], as
> > a..a is no valid subsentence of b..b).
> 
> That makes it very different from Lojban. In Lojban pretty much
> any terminated structure can be found inside of any other, and
> that's basically what the "terminator problem" amounts to.
> 
> > Besides elidable terminators, are there other problems why you
> > think lojban can't be expressed as a CFG (without the grammar
> > being way too large)?
> 
> I think ZOI is the only thing that makes Lojban non-CFG. Elidable
> terminators just make for a hugely impractical CFG.
> 
> Here is an example of how to handle elidable terminators in a
> small subset of Lojban:
> 
> http://groups.google.com/group/lojban/browse_thread/thread/90911b0611bb5a5e/555dbaf7addd93e6
> 
> The same principle could be extended to all terminators, but the
> size of the grammar would explode.

Huh!  I missed that.

Yeah, that's 2^{number of terminators} * {current number of rules}
rules or so, isn't it?  Ouch.

-Robin

-- 
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Lojban (http://www.lojban.org/): The language in which "this parrot
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